package com.web.handler;

import lombok.extern.slf4j.Slf4j;
import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.stereotype.Service;

import java.util.Collection;
import java.util.Iterator;

/**
 * @author xukk
 * @date 2017/6/5
 */
@Slf4j
@Service
public class MyAccessDecisionManage implements AccessDecisionManager {
    /**
     * decide 方法是判定是否拥有权限的决策方法，
     * authentication 是释CustomUserService中循环添加到 GrantedAuthority 对象中的权限信息集合.
     * object 包含客户端发起的请求的requset信息，可转换为 HttpServletRequest request = ((FilterInvocation) object).getHttpRequest();
     * configAttributes 为MyInvocationSecurityMetadataSource的getAttributes(Object object)这个方法返回的结果，此方法是为了判定用户请求的url 是否在权限表中，如果在权限表中，则返回给 decide 方法，用来判定用户是否有此权限。如果不在权限表中则放行。
     */
    @Override
    public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes) throws AccessDeniedException, InsufficientAuthenticationException {

        if (null == configAttributes || configAttributes.size() <= 0) {
            return;
        }
        /**
         * sys:*  sys:role:*
         *
         * sys  role  *
         * sys  *
         */
        ConfigAttribute c;
        String needRole;
        for (Iterator<ConfigAttribute> iter = configAttributes.iterator(); iter.hasNext(); ) {
            c = iter.next();
            needRole = c.getAttribute().trim();
            //authentication 为在注释1 中循环添加到 GrantedAuthority 对象中的权限信息集合
            for (GrantedAuthority ga : authentication.getAuthorities()) {
                String[] arr = needRole.split(":");
                String[] gar = ga.getAuthority().split(":");
                for (int i = 0; i < arr.length; i++) {
                    if (gar.length > i) {
                        if (gar[i].trim().equals("*") || arr[i].trim().equals("*")) {
                            return;
                        }
                        if (i == arr.length - 1) {
                            if (gar[i].trim().equals(arr[i].trim())) {
                                return;
                            }
                        } else {
                            if (!gar[i].trim().equals(arr[i].trim())) {
                                break;
                            }
                        }
                    } else {
                        if (arr[i].trim().equals("*")) {
                            return;
                        }
                    }
                }
            }
        }
        throw new AccessDeniedException("没有权限访问!");
    }

    @Override
    public boolean supports(ConfigAttribute attribute) {
        return true;
    }

    @Override
    public boolean supports(Class<?> clazz) {
        return true;
    }
}
